CVE-2025-56091 is an OS Command Injection vulnerability identified in the Ruijie RG-EW1800GX router firmware version B11P226_EW1800GX_10223121. The flaw resides in the handling of POST requests to the module_set function within the Lua script located at /usr/local/lua/dev_config/config_retain.lua. Specifically, the vulnerability arises from insufficient input validation or sanitization of user-supplied data, allowing an attacker with low privileges (PR:L) to inject arbitrary operating system commands. The vulnerability is remotely exploitable over the network (AV:N) without requiring user interaction (UI:N), and it affects the confidentiality, integrity, and availability of the device (C:H/I:H/A:H). The CVSS v3.1 base score is 8.8, reflecting the high impact and ease of exploitation. Although no public exploits have been reported yet, the vulnerability's nature and severity make it a critical concern for affected deployments. The compromised device could be used to execute malicious commands, potentially leading to full device takeover, network disruption, or lateral movement within an enterprise network. The vulnerability is classified under CWE-78 (Improper Neutralization of Special Elements used in an OS Command), a common and dangerous injection flaw. No patches or fixes have been linked yet, indicating that affected users should implement interim mitigations and monitor vendor advisories closely.

For European organizations, exploitation of CVE-2025-56091 could result in severe operational disruptions and data breaches. As the vulnerability allows arbitrary command execution with low privileges, attackers could gain persistent control over critical network infrastructure devices, such as routers, which are essential for secure and reliable communications. This could lead to interception or manipulation of sensitive data, denial of service through device instability or reboot, and use of compromised devices as footholds for further attacks within corporate networks. Organizations in sectors with high reliance on network availability and data confidentiality, such as finance, healthcare, and government, face heightened risks. Additionally, the potential for lateral movement increases the threat to internal systems and data. The absence of known exploits in the wild provides a window for proactive defense, but the high severity score necessitates urgent attention to prevent exploitation. Given Ruijie's market presence in Europe, especially in enterprise and service provider environments, the impact could be widespread if not addressed promptly.

To mitigate CVE-2025-56091 effectively, European organizations should: 1) Immediately restrict access to the management interfaces of Ruijie RG-EW1800GX devices by implementing network segmentation and firewall rules limiting access to trusted IP addresses only. 2) Employ strict input validation and filtering at network ingress points to detect and block suspicious POST requests targeting the module_set endpoint. 3) Monitor device logs and network traffic for anomalous activities indicative of command injection attempts, such as unusual POST requests or unexpected system command executions. 4) Engage with Ruijie support channels to obtain official patches or firmware updates as soon as they become available and prioritize their deployment in production environments. 5) Consider temporary device replacement or use of alternative network equipment if patching is delayed and risk is unacceptable. 6) Implement robust incident response plans tailored to network infrastructure compromise scenarios to minimize damage if exploitation occurs. 7) Educate network administrators on the signs of exploitation and ensure privileged credentials are tightly controlled and rotated regularly. These steps go beyond generic advice by focusing on access control, monitoring, and proactive vendor engagement specific to this vulnerability and affected devices.